assertNext

Expect an element and consume it with the given consumer, usually performing
assertions on it (eg. using Hamcrest, AssertJ or JUnit assertion methods).
Alias for consumeNextWith(Consumer) for better discoverability of
that use case.

Any AssertionErrors thrown by the consumer will be rethrown during
verification.

expectNoAccessibleContext

Expect that NO Context was propagated after the Subscription
phase, which usually indicates that the sequence under test doesn't contain
Reactor operators (i.e. external Publisher, just a scalar source...).

thenRequest

Request the given amount of elements from the upstream Publisher. This
is in addition to the initial number of elements requested by an
initial passed demand like with StepVerifier.create(Publisher, long).